1. Field of the Invention
The present invention relates generally to wrenches. More particularly, the invention concerns a ratchet wrench that provides constant drive to the output of the wrench upon rotational movement of the wrench handle in either direction.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Ratchet type wrenches are well known in the prior art. These types of wrenches function to apply force or torque to a nut or bolt without having to remove or replace the wrench at the end of each force-applying movement. Typically, such wrenches are used in conjunction with sockets configured for a particular nut or bolt size. While the typical prior art ratchet type wrenches provide for an acceleration of the work effort, they also exhibit an associated lost motion. More particularly, rotational movement of the wrench in one direction applies force, but during the return rotational movement no force is applied thereby resulting in wasted motion.
In the past, several attempts have been made to design ratchet wrenches that allow for drive during both the forward and return strokes of the ratchet handle. However, as a general rule, these past attempts have produced wrenches that are unduly complex, are difficult to use and are quite expensive to produce. Exemplary of these previous attempts are the prior art wrenches illustrated and described in the following patents:
Prior art U.S. Pat. No. 7,168,340 issued to Green describes a ratchet wrench in which a combination ring gear, sun gear and planetary gear system is used in combination with a drive pawl arrangement to achieve power drive in both directions of operation. Accelerated speed of operation is attained upon the return stroke as a function of gear sizing. In other embodiments, the planetary gear system is replaced with an intermediate gear assembly external to and inter-engaging both a drive and driven gear.
In the prior art patent issued to Gilberto, U.S. Pat. No. 5,009,132, a device in the nature of a wrench or the like is described in which reciprocatory rotary motion is converted to continuous rotation in one direction. The Gilberto device comprises first and second outer housings located in spaced relationship, a third intermediate housing lying between and joining the first and second housings, the intermediate housing having means for rotating it about a main axis, a ring lying within the intermediate housing and rotatable therein about the said main axis, the ring being formed with ratchet teeth on its outer periphery and with gear teeth on its inner periphery, a cluster of planetary gears carried within the ring and engaging the gear teeth of the ring, and a sun gear located within the cluster for rotation about the main axis and extending axially into engagement with both the first and second housings.